Has anyone setup their tstat to switch the fan from 'auto' to 'on' if the temperature differnece between the ground floor and 2nd floor is more than a certain amount (and obviously switch back to auto when the diff is reduced)?

I'm just getting a new tstat to replace my Intermatic 8900 (no fan control) and this is one of the things I'd like to try to setup. New tstat is the RCS TZ43 if that matters. I know this tstat has an optional remote sensor, but I'm not sure if I can leverage this or if I would need a separate zwave temp sensor?

I know this tstat has an optional remote sensor, but I'm not sure if I can leverage this or if I would need a separate zwave temp sensor?

The 2 optional remote sensors are wired. Not sure if the value of both the internal and the external sensors is accessible through Z-Wave independently or just the average of primary and secondary. Perhaps at @JOD knows, as he has the device and sensors.

I purchased the Prestige HD for the remote control capability to solve this issue. It controls to the temperature in the upstairs at night in my open foyer design and works well keeping a 2 degree difference, although the unit is pretty stupid overall. Looks nice, programs nice, but too dumb to even memorize that during the sleep schedule, I want to control off the remote instead of the main unit, which requires me to manually set each night. I also want Z-wave capability, but I could not get both at this time. I plan to replace the unit once I have a Z-wave solution that will do full remote control from another room.

RE: RCS TZ43, The remote sensors either replace the internal sensor, average with it or/and can display "Outside" temp as an additional temp reading on the T-stat (which could be any location you choose)

Unfortunatly you can't utilize the "Outdoor" remote sensor as an additional sensor with Vera, as Vera only display's one reading (the main reading) It's either not supported via Z-Wave through the T-stat or not supported via Vera, I dont know which.

I know this tstat has an optional remote sensor, but I'm not sure if I can leverage this or if I would need a separate zwave temp sensor?

The 2 optional remote sensors are wired. Not sure if the value of both the internal and the external sensors is accessible through Z-Wave independently or just the average of primary and secondary. Perhaps at @JOD knows, as he has the device and sensors.

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Logged

I'm sorry, my responses are limited. You must ask the right questions.

I'm pretty new at this, but would it be possible to set up an event to turn the fan on based on temp readings from something like an HSM100 placed on the 2nd floor? Perhaps some Lua code?

Yep, that should be possible. The HSM100 is battery operated though, and by default wakes up every 30 minutes. Which you could shorten, if desired, but that would decrease battery life. Some folks have hacked their HSM100's to be hard-wired.